Bradley’s model

As can be seen from the graph, Bradley s model gives conservative predictions of efficiency, mainly because he applied the approximation in equation 7.20, which was originally fitted to data obtained at radii between 1 and 2 cm, to radii up to rs = 2.223 cm where large discrepancies occur this leads to underestimates of separation efficiency. Bradley s model is still useful because it gives a lower estimate of efficiency, the actual grade efficiency curves are usually found to lie between those predicted by equations 7.9 and 7.21. 

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